In the operation of turbo power plants, there is the danger that the blades of turbine or compressor rotors will break. Upon breakage of a blade the broken pieces have considerable energy due to the generally high speed of rotation of the rotor, as a result of which the pieces are thrown substantially tangentially outward. In such case there is the danger that the broken pieces will pass through the housing of the power plant and do considerable damage. Particularly in the case of aircraft power plants, vitally necessary fuel or hydraulic conduits can be damaged, as a result of which the aircraft can crash or broken fragments can enter into the passenger compartment and injure passengers in the plane.
In order to avoid these consequences, the turbine housings are generally sufficiently reinforced at the likely locations where there can be blade breakage. As a result of the increasing energy of the blades in modern power plants due to the constantly increasing demands for higher speeds of rotation, the wall thicknesses of the housing and thus the weight of the power plant have had to be progressively increased in order to assure sufficient protection. In particular, for modern fan power plants, anti-rupture rings are known which consist, at least in part, of light weight materials of high strength and high energy absorption, such as, for instance, aramide fibers. In this way, high protective action can be advantageously combined with low weight of the anti-rupture ring.
Upon overhaul or repairs on power plant housings, it is frequently necessary to carry out tasks, such as testing for cracks or galvanic processes for which it is necessary temporarily to remove the anti-rupture ring. Removal of the anti-rupture ring by axial displacement is frequently questionable since the housing rings have threaded flanges on both sides which substantially increase the difficulty of displacement of the anti-rupture ring.
The technique of manufacturing anti-rupture rings with fiber reinforcement, however, requires heat curing of the resin matrix. With a tightly wound anti-rupture ring, variable stresses are produced in the ring and housing as a result of different thermal expansions and shrinkages, which may be undesired or, upon cooling, lead to spaces between the ring and the housing.